Apparatus for producing light waves



Sept. 1, 1931. o. "r. M ILVAINE APPARATUS FCSR PRODUCING LIGHT WAVES Filed Feb. 23. 1928 HOV Ora-n T. Mc.I1va.-ine

Inven tor Attorneys Patented Sept. 1, 1931 UNITED STATES PATENT OFFICE ORAN T. MGILVAINE, OF EAST CLEVELAND, OHIO, ASSIGNOR TO MOILVAINE PATENT CORPORATION, OF ST. CHARLES, ILLINOIS, A =CORPORATIOIN' OF DELAWARE APPARATUS FOR PRODUCING LIGHT WAVES Application filed February 23, 1928. Serial No. 256,234.

This invention relates to the-production of light rays and has for its objects the provision of new and improved expedients for the production of light rays of any desired wave length and with minimum consumption of power. The apparatus herein described was originally devised and constructed for the principal object of producing ultra violet light more cheaply and conveniently than heretofore, but I have found that it also serves to produce visible rays with a lower expenditure of energy than any filament type of lamp heretofore known and is superior to the discharge type of illuminating tube in that it has a wider range of possible colors and enables the production of white light and sunshine effects more easily. Hence I do not confine .myself to any one part of the spectrum;

I have observed that when either magnetic or electrostatic vibrations of the proper frequency are impressed upon a body of gas at the proper pressure enclosed withina suitable container, the whole body of that gas glows with a color and intensity determined by its composition and pressure and the intensity of the field to which it is subjected. The frequency required is of the ordercorresponding to a wave length of 100 to 1000 meters more or less and is obtained by electrical oscillations in a resonant circuit controlled by an electric valve of some kind; and one of the features of my invention is the combination of this valve with the emitting application itself.

In the drawings accompanying and forming a part of this application Figs. 1, 2, and 3 are diagrammatic views of three simple glow lamps and their circuits embodying 4.0 my invention.

Every installation includes a globe 1 of material which is transparent to the rays desired. For ordinary visual light common glass is suflicient but for ultra violet rays special materials such as quartz or different qualities of Pyrex glass are employed. I do not give formulas or compositions of glass since the Corning Glass Works of Corning, New York; and other manufacturers have glass compositions on the market which are at least as pervious to ultra violet rays as is the atmosphere itself. Inside this globe I locate a filament 2, of tungsten, tantalum, molybdenum, or other high melting point substance which shall both constitute a source of heat and of electrons. Around this filament I locate a grid element 3 and a plate or cathode element 4. Suitable terminals are connected thereto and sealed -into the glass, which is also in practice provided with a suitable base (not shown).

I have shown the device as arranged for excitation by. a 110 volt alternating current circuit, the connections here comprising: a transformer having a core 5, primary winding 6, and two secondary windings 7 and 8; together with an-inductive coupler 9 between the grid and plate circuits, a by pass condenser 10 to'facilitate the flow of radio frequency current; and a grid-condensergrid-le'ak-unit 11 adapted to maintain a proper grid potential.

The winding 7 is employed mainly to secure a low potential for the filament. A 110 volt filament can be used and the line current connected directly thereto, but such a filament is necessarily of very fine wire,

andis rather deficient in ability to withstand electron bombardment. A center tap 12 to the winding? is connected to one end of one of the coils comprising the coupler 9, the other end of that coil being connect ed to the grid 3 by way of the condenser and high resistance unit 11. The other coil comprised in the coupling 9 has one end connected to the plate 4 and the other end to one terminal of the winding 8. The opposite end of said winding 8 is connected to the middle tap 12. The winding 8 is bridged by a condenser 10 for the purpose of saving the radio frequency current the need to go through the iron core transformer coil 8.

The current in .the filament 2 both produces heat, light,-and electrons; whenever the alterations of the A. C. produce a negative polarity at 2 coupled with a positive polarity at 4 as electronic current flows from the filament to the plate and thence back to the filament via 9, 8, and The relation between the coupler coils 9 causes this momentary current to charge the grid in such wise as to interrupt the flow with the result that an oscillation is set up in case the proper relation exists betwen the capacity and inductance of the circuit. I have shown the coupler 9 as a variable, but this is not necessary if the right quantities are chosen originally for the frequency desired. The high frequency field thus produced inside the globe 1 sets up a lumination of the gas, assuming the proper pressure, which should ordinarily be very low, e. g. 30 to 100 microns of mercury. The pressure permissible varies with the composition of the gas as also does the color of the light. The intensity varies with the pressure of the gas, the frequency, and the E. M. F. applied. Almost any gas will exhibit these phenomena although those gases are the best which.

have little or no corrosive or combining power. I prefer to use nitrogen, helium, argon, neon, krypton, xenon, or mercury vapor, or a mixture of two or more thereof. When a readily ionizable substance like neon or mercury vapor is employed the light produced is augmented by a third effect, namely a luminous discharge between the filament 2 and the plate 4. This third effect is not directly due to radio frequency oscillations and the amperage thereof may vary all the way from comparatively little to several ampers depending upon the composition and pressure of the gas, being lowest With a difiicultly ionizable gas like nitrogen and highest with the readily charged gases. Asa result of this three-fold source the entire globe becomes filledwith a glowing light which can be made very intense, and which yields all manner of wave lengths and colors according to the gas and glass.

In Fig. 2 I have supplemented the effect of the electrostatic field within the globe by a magnetic field. The filament, grid, and plate appear as before as do also the elements of the main transformers 5, 6. 7. 8. The coupler 9 has its secondary in the grid circuit as before but its primary, instead of being connected in the plate circuit is joined to a closed oscillating circuit of low resistance comprising a series of helical turn 20 surrounding the globe and including also a condenser 21 of proper capacityto form with such coil 20 a resonant circuit; I have suggested a capacity of .01 mt. for this condenser, but this will vary with the sizeand number of turns of the coil 20/ The coil 8, instead of being connected to the coupler 9 is here connected directly between the plate on the one hand and the filament on the other, and is also connected via condenser 23 (here suggested as of .002 mf.) to the magnetic circuit, and the radiofrequency circuit is now completed by a connection 24.

In the device shown in Fig. 2 there is strictly speaking only one resonant circuit, namely: the magnetic circuit comprising the coil 20 and condenser 21, and coupler primary 9; the grid circuit and plate circuit are forced to follow the oscillations in the magnetic circuit. It is necessary to make sure that none of the elements inside the globe are short circuited else the, alternating currents induced therein will melt the same. Preferably the grid and plate consist merely of open loose ended wire coils. In the form shown in Fig. 1 there can be closed cages or nets if desired, it being necessary merely to allow free escape of light rays.

In the form shown in Fig. 2 the light source is four-fold, viz: the direct rays from the filament; the gas glow due to electrostatic field created by the plate current; the gas glow due to the electromagnetic tield created by the coil 20; and the gas are be,- tween the filament and plate.

The resulting light'is in many respects very similar to sunlight. especially as regards its chemical and therapeutic effects. and resembles day light in its diffusion and general color. It is capable of use in vcry large size installations and lends itself also to small sized units although I prefer to make it in rather substantial sizes. It also can be used either as a source of actinic or therapeutic rays.

The device shown in Fig. 23 operates in the same way when connected to a circuit, such for example as that shown in Fig. 1, though the smaller extent of the anode causes the volume of the glowing space to be smaller than in Fig. 1.

It will be understood that I do not limit myself to the particular construction of globes and electrodes heroin illustrated, or to the particular oscillating circuits since both these features may be widcly changed within a proper construction of these my Letters Patent.

Having thus described my invention what I claim is:

1. A source of light rays comprising a globe having therein an ionizable gas under low pressure, a filament, an anode and a control elect-rode surroumling said filament and made of a pattern to facilitate the emission of light rays, a source of current for said filament, high frequency oscillating circuits including said filament and said anode and controlling electrode and connections establishing an external circuit bctwcen said filament and anode, said external circuit containing a source of E. M. F.

2. In a lamp, in combination, a transparent container holding ionizable gas, a cathode, an anode, and a control electrode sealed in said container, said cathode being of an electron emitting type, and external circuits connecting said electrodes together and including inductances and capacities whereby highvfrequenc'y oscillations are pro duccd and maintained, that circuit which contains the anode and cathode containing a source of potential suflicient to produce an oscillating current flow between saidanode'and cathode.

3. In a lamp, 1n combinat on, a transparent container holding ionizable gas, a

cathode, an anode, and a control electrode 80211.6(1'111 said container, said cathode being of an electron emitting type, and means 1n- ,cluding said cathode, anode and controlelectrode for impressing upon the space insldo said container a high-frequency field,

said means also acting toimpose a sufiicient electromotive force between said anode and said cathode to render the gas luminous.

4. In a lamp, in combination, a transparent container holding ionizable gas, a cathode, an anode, and a control electrode sealed in said container, said cathodefbeing of an electron emitting type, means for impressing upon the space inside said container a high frequency electrostatic ,field and means for additionally imposing an E. M. F.

between certain of said electrodes, whereby said gas is rendered luminous.

. 5. In a lamp, in combination, a transparent container holding ionizable gas, a cathode, an anode, and a control electrode sealed in said container, said cathode being of an electron emitting type, means for imposing upon the space insidesaid container ahigh frequency electromagnetic field and means for additionally impressing an E. M. F. between said anode and cathode, whereby said gas isrendered luminous.

V 6. Light producing apparatus comprising, in combination, a transparent container holding ionizable gas, a filament therein adapted when heated to emit electrons, a

control electrode of open pattern surrounding said filament, an anode of open pattern surrounding said control electrode, a low tension transformer operatively connected type and being joined into two oscillating,

circuits with said anode and control electrode respectively; and means for imposing a sufiicient electromotive force in the first of said circuits to produce oscillation.-

8. A source of light rays comprising a transparent container having therein an ionizable gas under sub atmospheric pres sure, a cathode of electron-emitting'type located inside said container, an anode and a control electrode surrounding said cathode and made of a pattern to permit the passing of light rays, means for energizing said cathode to cause the emission of electrodes, oscillating circuits. including said ,i cathode and anode and controlling electrode, and

connections for'cstablishing an external circuit between said anode and cathode, said external circuit containing a source of electromotive force.

9. A light producing apparatus comprising in combination a transparent container holding ionizable gas, a cathode therein of electron-emitting type, a control electrode of open pattern surrounding said cathode, an anode of open pattern surrounding said control electrode, means for energizing said cathode to cause the emission of electrons, a

source of electro-motive .force having its terminals connected, the one to said cathode and the other to said anode, and a resonant controlled circuit connected to said control electrode and operatively coupled, to the' anode circuit to produce oscillations.

In testimony whereof I hereunto afiix my signature.

ORAN .T. MGILVAINE.

to said filament to heat the same, a higher 

